Preheat the oven to 400. In a medium bowl, soak the flax in 6 Tbsp. of water for at least 2 minutes. Add the vanilla and whisk until small bubbles are present. Add the flour, sugar, salt and remaining water and whisk together. The batter should be fairly thin. If needed, add a little more water. Grease and flour a cookie sheet. Using a tablespoon of batter for each cookie, drop 3 circles of batter on the cookie sheet. Seriously, don't get brave and try to do more than 3 cookies at once. The cookies have to be really hot to form correctly. If they are too cool, they crack. Also, you need time to let your little fingies cool off! Roll the cookie sheet around to spread the batter out until each cookie is about 3 1/2" in diameter. Bake at 400 degrees until the edge of the cookies are browned. Remove a cookie from the pan with a spatula. Fold the cookie in half so that the bottom side halves of the cookie are folded in towards each other (now you've got a half circle). Place a paper strip inside. Place the middle of the folded edge (open side up) perpendicularly on the rim of the mug and draw the corners of the cookie down (one into the mug and one outside). Now you've got a fortune cookie! If this is too big of a pain, just fold the cookie in half, and then in half again (bringing the 2 corners together). Repeat with the 2 remaining cookies, then start another batch. May all your cookies be fortunate!